We report the first experimental demonstration of two-dimensional spatial solitary waves in second-order nonlinear optical material. When an intense optical beam is focused into a phase-matchable second-order nonlinear material, the fundamental and generated second-harmonic fields are mutually trapped as a result of the strong nonlinear coupling which counteracts both diffraction and beam walkoff.

• Received 14 December 1994

DOI:https://doi.org/10.1103/PhysRevLett.74.5036